PG is a group of physiologically active substances synthesized in animal tissues from eicosapolyenoic acid such as arachidonic acid. Said compound is known to show a wide range of pharmacological actions such as hypotensive action, platelet aggregation-inhibitory action, vasodilating action, blood flow increasing action, gastric juice secretion-suppressing action, intestine hyperkinetic action, oxytocic action, diuretic action, bronchodilating action, contracting action and so on.
PG is hardly absorbed by oral administration and therefore generally administered by injection. Injections, however, give pain to patients.
Injections, moreover, require patients to go to the doctor by themselves, giving burdens on the patients in terms of time and physical labor, and development and practical application of a dosage form other than injection have been desired. In doing so, it is essential to solve technical problems with regard to achieving high bioavailability of a slightly-absorbable drug and the stabilization of unstable PG.
The present invention aims at solving the above-mentioned problems. That is, the present invention aims at solving the above problems by providing PG, which has been conventionally administered as injections, in other dosage forms and employing other administration method.